1. Field of the Invention
The present invention relates to a liquid crystal display module, and more particularly, to a liquid crystal display module capable of reducing the manufacturing cost and improving the manufacturing efficiency.
2. Discussion of the Related Art
In the recent information society, the importance of display devices serving as a visual information medium is increasing. However, it was a large problem in cathode ray tubes or television tubes that were mainly used as the display device in that their weight and the size were large. Accordingly, many kinds of flat panel display devices have been recently developed so as to solve the problems of the cathode ray tubes or the television tubes.
Examples of the flat panel display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electro-luminescence (EL). Most of the flat panel display devices have been put to practical use and have been put on the market.
Out of the flat panel display devices, the application range of the liquid crystal display has widened because the liquid crystal display can be manufactured to be light and thin and can be driven under low power consumption. Accordingly, the liquid crystal display has been used as a personal computer such as a notebook PC, an office automation equipment, an audio/video equipment, an interior/outdoor advertising display device. The liquid crystal display displays a desired image on the screen by controlling the transmission amount of light beam depending on video signals applied to a plurality of control switches arranged in a matrix format. The liquid crystal display has rapidly grown to be the large-sized liquid crystal display with the high-resolution because of a technology for the mass production and the research and development.
Generally, the liquid crystal display includes a liquid crystal display module and a driving circuit unit for driving the liquid crystal display module.
The liquid crystal display module includes a liquid crystal display panel in which liquid crystal cells are arranged between two glass substrates in a matrix format, and a backlight unit providing light to the liquid crystal display panel. The liquid crystal display module includes optical sheets that allow light traveling from the backlight unit to the liquid crystal display panel to travel in a vertical direction. The liquid crystal display panel, the backlight unit, and the optical sheets have to be fastened in an integrated form so as to prevent the loss of light, and also have to be protected from an external impact. For this, the backlight unit including edges of the liquid crystal display panel and a liquid crystal display case surrounding the optical sheets are provided.
The backlight unit of the liquid crystal display module may be classified into a direct-light type backlight unit and an edge-light type backlight unit. In the edge-light type backlight unit, a fluorescent lamp is installed outside a flat panel and emits light to the entire surface of the liquid crystal display panel using a transparent light guide plate. In the direct-light type backlight unit, a light source is installed in the rear of the liquid crystal display panel and directly provides light to the liquid crystal display panel. Because several light sources are installed in the direct-light type backlight unit as compared with the edge-light type backlight unit, a luminance of the liquid crystal display can increase and a light emitting surface can widen. Therefore, in case the large-screen liquid crystal display panel such as a LCD TV is required, the direct-light type backlight unit is generally used in the liquid crystal display module.
A related art direct-light type backlight unit includes a plurality of lamps providing a liquid crystal panel with light, a bottom cover receiving the plurality of lamps, a diffusion plate that is positioned to cover the entire surface of the bottom cover and diffuses the light emitted from the plurality of lamps to irradiate the diffused light to a liquid crystal display panel, and a plurality of optical sheets stacked on the diffusion plate. The diffusion plate diffuses the light emitted from the plurality of lamps toward a front direction of the liquid crystal display panel, and thus uniforms the distribution of the light irradiated to the liquid crystal display panel. The diffusion plate is formed by coating a light diffusion member on both surfaces of a film formed of a transparent resin.
In the related art direct-light type backlight unit, a large amount of heat is generated by cold cathode fluorescent lamps used as the lamp, and the diffusion plate hangs down by the heat as well as the influence of gravity. If the diffusion plate hangs down, the diffusion amount of light in a hang-down portion of the diffusion plate is different from the diffusion amount of light in a non-hang down portion of the diffusion plate. Hence, the amount of light irradiated to the liquid crystal display panel is not uniform, and even bright lines may appear in the lamps.
Accordingly, a plurality of lamp guides capable of fixing the lamps and preventing the hang down of the diffusion plate were proposed.
However, as a large number of lamps are used in the liquid crystal display module in accordance with the recent market trend toward the large-screen liquid crystal displays and the length of the lamps used in the liquid crystal display module becomes longer, heat generated by the lamps increases. Therefore, a large number of lamp guides are required so as to prevent the hang down of the diffusion plate.
As the number of lamp guides increases, the manufacturing cost of the liquid crystal display module increases, and also a manufacturing process is complicated to cause a reduction in the manufacturing efficiency.